Q: What's up with the yellowjackets?Why are they hanging out at my picnic table, and what can I do to get rid of them?

A:The yellowjacket population is at its peak at the end of the summer, as food is becoming scarce– which makes fall the worst time of the year for yellowjackets– but they're also noticeable this time of year as they search for food at picnic tables and in trash cans. In addition, their nests are often stirred up by people doing lawn work.

Yellowjackets are wasps, and like their relatives the mud daubers, cicada killers, and European hornets, they fold their wings lengthwise when at rest, and are yellow and black in color. Their close relatives, the bald-faced hornets, look similar but are black and white instead.

Like all wasps, yellowjackets prey on a wide variety of insects and other arthropods and can be considered beneficial when they stay out of your way. Yellowjackets are unusual in that they forage on foods consumed by people, especially sweets and meats. They love to visit garbage cans, rotting fruit, rotting meat, and soft drinks.

Yellowjackets are venomous and have a stinger that can inject very painful venom into the skin. Some build underground nests while others build aerial nests. A paper envelope surrounds yellowjacket nests, and inside are layers of comb with brood cells similar to bee cells. Normal colonies have from 75 to 5,000 worker yellowjackets.

Yellowjackets are at their most dangerous when one of their underground nests is disturbed or stepped on– this usually occurs in wooded areas and can result in hundreds of stings. The stinger of the yellowjacket is not barbed like that of the bees, so they can sting repeatedly.

If you're stung, the treatment for a normal reaction is to apply an icepack, take a pain reliever, and wash the wound carefully. Oral antihistamines usually reduce any swelling. Calamine products can reduce the itching. Medical attention may be needed if the sting is around the throat, nose, or eye area.

Immediate and aggressive treatment is necessary for people who are allergic to stings. Symptoms include closing of the throat, severe swelling, and hypotension.

Here are some yellowjacket safety tips:

–Don't swat at them. They sting when disturbed, and they release a chemical that causes others to join in the attack.

–Caution children about playing in overgrown areas. These are prime nesting areas.

–When eating outside, look before you sip. The insects are attracted to sweet sticky foods like soda and juice.

–Cover trash containers so they can't get in.

If you decide to treat nest yourself (ideally, you should use a professional), they should be located during the day when the workers are going and coming on a regular basis. Return late at night to treat the nest with a liquid insecticide. The impact on the environment is minimal due to the quick breakdown of these products and due to the fact that you are spot treating a small area. However, there are also some traps on the market that use sugar water as an attractant, and there is an aerial spray called Orange Guard that is organic. But remember, the destruction of individual colonies may not eliminate all the yellowjacket workers in an area where food is available because yellowjackets are capable of flying a mile from their colonies in search of food.

Naturally, the best way to keep yellowjackets away is to deny them a food source. If begun early in the summer and carried out through mid-autumn, keeping trash containers closed tight and emptying them frequently can keep yellowjackets at bay. Another idea: place a no-pest strip to the inside of the lid of a closed trash container to kill the yellowjackets that may become trapped inside.